The increasing demand for wireless telecommunication services has resulted in the growth of many wireless telecommunications systems and an increase in the number of roaming wireless subscribers. Some efforts that have been implemented to accommodate and distribute the increased traffic load propose that the traffic load be distributed among a number of switches, such as Mobile Switching Centers (MSC), such that they constitute a switch pool, or MSC pool, for the network. Such a switch pool offers many advantages to both subscriber and network service provider in the form of more efficient utilization of network resources. Advantages realized by the use of the switch pool include load sharing of network components and increased capacity and/or coverage without the addition of more switching elements.
There are, however, known limitations and disadvantages of a conventional switch pool. The most flexible methods of load distribution in telecommunications networks using such pools function on a per transaction basis. This technique is adequate for connection-oriented messages, e.g., where a connection is being established with the initial message, and the switch pool which handles the initial message controls the resulting call. Such systems and methods suffer from inefficiency, however, in the handling a paging query and corresponding paging response.
In particular, the paging request is a connectionless message. That is, no connection is established between the querying switch and the responding access node such that it may be difficult to identify the querying switch in the switch pool. Should a different switch be selected during the time interval preceding a response, there is no ready mechanism for associating the response to the paging switch. In some circumstances, the probability can be small that the same switch that sent the paging query would be the same switch selected to receive the response. Therefore, the switch that receives the paging response must check to see which switch handled the paging query and send the paging response to that particular switch. Once the connection is established, this routing procedure is also used for any messages subsequent to the paging response. Using the resources of both switches is an inefficient use of capacity.
Due to the above-referenced and additional problems in efficiently routing messages in a telecommunications network using a switch pool, improved methods and systems for selecting switches from within the switch pool would provide significant advantages by allowing the switch initiating a paging request to be re-selected for the paging response as well. Such systems and methods would substantially eliminate the redundant use of resources in a telecommunications network for most mobile-terminating calls. More efficient use of switches in a switch pool would produce numerous advantages including allowing for increased telecommunications traffic in the network and a reduction of the switch hardware required for a given level of traffic. Some of the advantages of the invention are summarized below.